Underground Internet for Plants

Underground internet for plants described in an article in New Scientist, 13 November 2010, p14. Approximately 80 percent of plants are known to form a symbiotic relationship with filamentous fungi called mycorrhizae that help plants obtain water and minerals. Research carried out at south China Agricultural University, Guangzhou indicates the mycorrhizal network around plants that are growing together helps plants communicate. The researchers grew pairs of tomato plants in pots so they shared the same mycorrhizal network. They then sprayed one plant with a disease causing fungus and waited 65 hours and infected the second plant. Plants that shared a mycorrhizal network were more likely to activate defensive genes and enzymes, and were less affected by the disease.

Plants are already known to send signals by airborne chemicals, so the researchers prevented this by encasing them in airtight bags, so any signals had to go within the soil. Although this disease mitigating communication has only been shown to work in the laboratory, mycorrhizal networks have been shown to be important for plant health out in the real world. Some are extremely large, extending through whole forests, and they can also link plants of different species together. Dan Durall of the University of British Columbia, Kelowna, Canada, commented: “It's a very robust system that could allow for the movement of signal proteins over many metres.”

Editorial Comment: This plant-fungi relationship is another reminder that symbiosis is the norm, rather than the exception, in the living world. This is exactly what you would expect in a world that was created as a functioning whole by a creative designer. We predict that the minority of plants that don’t seem to have a symbiotic relationship with mycorryhiza will be found to have lost it - a suspicion that might be established through detailed analysis of their fossils. These plants are probably tough enough to survive through the pre-existence of back up mechanisms. This however is not evolution, as such loss is degeneration. The importance of the symbiotic relationship between plants and mycorrhizal networks is seen when attempts at reforestation of land fails because the soil fungi no longer exist. (Ref. botany, mycology, symbiosis)